I draft my patterns in AutoSketch, which is a smaller application of AutoCad. I draw each step out in there first, then I write the actual step-by-step instructions in Excel. Excel is really nice for word processing because you don't have to create text boxes - you can just place the text and pictures wherever you want them. Excel is also nice because I can make just one file with several pages - Supply list, cutting instructions, shop notes (what the quilt shop will want to have on hand to sell when this class is being taught), sewing instructions, Cover and back sheets. Usually, I then save the excel file as a pdf file because it's more accessible to more people.
I use my EQ4 to take some of the math out of the size options. I can experiment with different size borders, etc. in there to figure the finished quilt sizes and save the calculator work!